1. Field of the Invention
This invention relates generally to cable suspended lighting assemblies and more particularly to a system for leveling a linear lighting fixture about its longitudinal fixture axis.
2. Antecedents of the Invention
A popular installation for linear lighting assemblies has been the suspension of lighting fixtures from braided steel cables. A linear fixture was supported by a pair of braided steel cables, the upper ends of which were anchored to a ceiling support and the lower ends of which were locked in a bore of a cable anchor. The cable anchors were positioned in registration with the longitudinal axis of the fixture, equidistantly spaced from the ends of the fixture. The cable anchors included a spring loaded locking clamp for adjustment of the effective length of the cable so that the fixture could be horizontally leveled along its longitudinal axis.
In addition to wiring and fixture costs, a significant factor in the total cost of lighting was the installation. While leveling the fixture along its longitudinal axis was relatively simple, the more difficult task was leveling the fixture about its longitudinal axis. Weight imbalances due to ballasts, sockets, related wiring, brackets and mechanical components carried within the fixture resulted in moments about the longitudinal axis of the fixture which were required to be balanced in order to hang the fixture in a horizontal plane.
Previous techniques for leveling a cable suspended fixture about its longitudinal axis included the installation and positioning of counterbalance weights within the fixture housing. Such task was labor intensive and time consuming, with workers standing on scaffolding or ladders.
The present invention comprises a leveling system for a linear lighting assembly suspended from cables. The cables hang substantially vertically from a ceiling anchor with each cable being received within the bore of a cable anchor attached to the fixture.
The cable anchor is secured to a bracket which pivots about an axis parallel to the longitudinal axis of the fixture. The bracket may be carried in an assembly strut which joins elongate side extrusions of the fixture.
The strut comprises an open channel having parallel side walls and a bottom. A bracket pivot extends through the side walls of the strut. Positioned between the strut bottom and the underside of the bracket on one side of the pivot is a compression spring while a screw extends through the bracket on the other side of the pivot and bears against the bottom of the strut. Rotation of the screw varies the plane of the cable anchor bracket relative to a reference plane of the fixture to horizontally level the reference plane and compensate for fixture weight imbalance.
From the foregoing compendium, it should be appreciated that it is an aspect of the present invention to provide a leveling system for a cable suspended lighting fixture of the general character described which is not subject to the disadvantages of the antecedents of the invention aforementioned.
It is a feature of the present invention to provide a method of leveling a cable suspended lighting fixture of the general character described which is simple to practice.
A consideration of the present invention is to provide a method of leveling a cable suspended lighting fixture of the general character described which reduces installation labor costs.
Another aspect of the present invention is to provide a leveling system for a cable suspended lighting fixture of the general character described which is relatively low in cost and suitable for economical mass production fabrication.
An additional feature of the present invention is to provide a leveling system for a cable suspended lighting fixture of the general character described whereby a reference plane extending through the fixture is horizontally leveled in the presence of a weight imbalance about the longitudinal axis of the fixture by varying the angle of an adjustment bracket.
A further consideration of the present invention is to provide a leveling system for a cable suspended lighting fixture of the general character described whereby the lighting fixture may be leveled about its longitudinal axis utilizing an adjustment screw.
Yet a further aspect of the present invention is to provide a leveling system for a cable suspended lighting fixture of the general character described which compensates for a weight imbalance varying the position of one portion of the fixture relative to a reference plane of the fixture.
To provide a leveling system for a cable suspended lighting fixture of the general character described which reduces the necessity for field installation of counterbalance weights is a further feature of the present invention.
Further aspects, features and considerations in part will be obvious and in part will be pointed out hereinafter.
With these ends in view, the invention finds embodiment in the various combinations of elements, arrangements of parts and series of steps by which the aforesaid aspects, features and considerations and certain other aspects, features and considerations are attained, all with reference to the accompanying drawings and the scope of which will be more particularly pointed out and indicated in the appended claims.